COVID-19

SARS-CoV-2 emergence in late 2019 quickly led to the coronavirus disease 2019 (COVID-19) pandemic. The pandemic was met both with unprecedented medical countermeasure development and its application for large numbers of patients. Simultaneously, also present were stark disparities in surveillance and recognition of cases; differences in the ability to acquire and field these same countermeasures; and, the consequences of health systems historically under-resourced, under stress, and unable to best apply usual non-pharmacologic case management measures. Community action proved equally diverse, with wide variation even in small geographic areas in promotion of physical and social distancing, mask use, and uptake of laboratory testing and vaccine use. High case burden and global impacts unfortunately afforded the opportunity to learn myriad host, pathogen, and environment nuances of COVID-19 not well explored in most respiratory virus diseases. This chapter details these lessons.